2019/05/17 by Zhih-Cheng Ma, Kun-An Chiu, Kun‐An Chiu +2 · 2 citations
Physics and Astronomy · Engineering · #GaN-based semiconductor devices and materials #Acoustic Wave Resonator Technologies #Metal and Thin Film Mechanics
paper · doi:10.7567/1347-4065/ab0ad3
Abstract Microwave plasma using a gas mixture of N 2 and H 2 has been applied for the nitridation of m -plane sapphire substrate to form a thick epitaxial AlN film. The X-ray diffraction results show that the AlN films formed on the sapphire surface by nitridation for a period from 10–60 min are in (10 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mover accent="true"> <mml:mn>1</mml:mn> <mml:mo stretchy="true">¯</mml:mo> </mml:mover> </mml:math> 0) orientation and have an epitaxial relationship with the substrate. The thickness of the nitride film increases with nitridation time and approaches about 0.5 μ m after nitridation for 1 h, while the film surface becomes rough. The film quality is reasonably good, as evaluated with the X-ray rocking curve of (10 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mover accent="true"> <mml:mn>1</mml:mn> <mml:mo stretchy="true">¯</mml:mo> </mml:mover> </mml:math> 0) AlN. Faceted voids in the sapphire substrate underneath the AlN are also observed with inclined a -plane facets after nitridation.